1. Field of the Invention
The present invention relates generally to network routing, and more particularly, to dynamically determining regional address locations for best exit routing based upon route deaggregation and route selection preferencing.
2. Background of the Invention
The growth of the Internet, and the World Wide Web (WWW) in particular, has led to enormous increases in the amount of traffic flowing over the group of connected networks that comprise the Internet and connected network systems. Access providers such as Internet Service Providers (ISPs) provide connections for businesses and individuals to connect to the Internet and access the WWW. ISPs must interconnect in order to allow their customers to reach points on the Internet serviced by other ISPs.
The exchange of traffic between Internet service providers (ISPs), where traffic from one ISP's customers is destined for customers of another ISP, is referred to as “peering.” This is contrasted with “transit,” where the traffic that is exchanged is destined not only for the receiving ISPs customers, but also for other users throughout the Internet (which are in turn reached via the receiving ISPs peering connections). ISPs generally charge for transit connections, while peering connections do not involve an exchange of money. Therefore, peering provides free bi-directional exchange of customer traffic between ISPs whereas transit provides paid access to the entire Internet. For example, large ISPs with their own national backbones often mutually agree with other large ISPs with national backbones to freely exchange their customer data. An Internet backbone is the central part of an ISP's network which transports data between edge, or regional, parts of the networks and Internet peering points. Instead of peering, large ISPs that have a national backbone offer transit service to smaller, regional ISPs who cannot offer reciprocal backbone sharing. These smaller ISPs use the larger ISPs national backbones to reach users outside of their service areas.
Peering connections are based upon the underlying assumption that traffic flows between two different ISPs will be approximately equal. These mutual agreements to exchange information traffic (bandwidth) freely and without charge do not make economic sense if one peering partner is forced to carry substantially more traffic than another. Unbalanced bandwidth may affect peering relationships because most peered data is routed between peers using a routing method called “hot potato routing.”
In hot potato routing, an originating peer network carrying a customer's traffic finds the nearest entry point to the destination peer's network and drops the traffic off as soon as possible. There is no incentive for a carrier to transport additional bandwidth if a peer network is available to carry the traffic. Likewise, the destination peer network will send returning data to the originator's network from its nearest entry point into the originator's network. If the two exchange points used for this data transfer are geographically dispersed, this type of routing creates an asymmetric routing path between two network terminations whereby one “to” path travels primarily on the destination peer's network and the “from” path travels primarily on the originator's network. If the amount of bandwidth used is symmetric in both directions and the two networks have similar geographic scope then this creates a fair economic exchange. Each peer carries half the bandwidth and each peer has (presumably) one paying customer to pay for its half of the transfer. This is the basic barter proposition underlying Internet peering.
However, although Internet peering models are generally based upon the assumption of symmetric bandwidth between peers, this assumption has proven to be flawed. The growth of the WWW and increases in WWW traffic have exacerbated the problem of bandwidth asymmetry. Web content providers tend to transmit copious amounts of data. Bandwidth between Web content providers and the individuals who view Web content is often unbalanced. Web content providers typically send as much as 4 to 10 times more bandwidth than they receive. An individual might request a Web page by sending just a single address or page request, whereas the Web page content provider returns multiple Web pages to the individual, thereby consuming large amounts of bandwidth.
For example, consider a scenario between ISP A, servicing an individual, and ISP B, servicing a Web content provider. ISP A and B both use hot-potato routing, dumping network traffic off at the closest entry point to the peering ISP. ISP A receives a request for a Web page, and routes the request such that the request is carried by ISP B for a majority of the distance traveled (hot potato routing). ISP B returns the requested Web page, constituting a considerably larger amount of bandwidth than the initial request from the individual. ISP B similarly uses hot potato routing, which results in ISP A carrying the Web traffic for the majority of the distance traveled. ISP A is forced to carry more than its fair share of the bandwidth traffic burden in this scenario. Furthermore, ISP A is unable to charge its own customers more for the extra bandwidth, because the entity originating the extra bandwidth is a customer of ISP B. The current peering system does not provide the proper economic incentives for an ISP to increase its bandwidth, because the increased bandwidth may be consumed by the ISP's peers.
Web content providers are often constrained by the bandwidth limitations they experience through their ISP. Some Web content providers attempt to solve this problem by becoming multi-homed, i.e., by contracting for service with multiple ISPs to purchase additional bandwidth capacity and presumably to purchase redundancy. However, the addition of redundant paths to each potential client terminal results in increased complexity. Being multi-homed requires thinking and acting like a backbone Internet network operator, and having the capability to properly route traffic.
The resulting burden of best path management is a difficult task and not one that will likely be mastered by most Web content providers. The Border Gateway Protocol (BGP) (which is used to route data between networks on the Internet) is a poor tool, with limited best path information available to the automated decision making process in the router. Micro-engineering good connectivity to many providers requires substantial knowledge of not only the BGP protocol and its rules but also requires substantial knowledge of the network structure and operational capabilities of the downstream providers themselves.
Thus Web content providers, as well as other Internet consumers, need a system allowing them to purchase large amounts of network bandwidth without requiring each Web content provider to become an expert at Internet routing. However, because Web traffic contributes substantially to the peering bandwidth asymmetry problem, a method is required to compensate all network carriers for the Web bandwidth they carry, including Web traffic that originates in a network peer. An economically rational system is needed for providing Web bandwidth, whereby Web content providers pay the true cost of their service and ISPs are paid for the Web bandwidth that crosses their network systems.